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| author | Nathan Chancellor <nathan@kernel.org> | 2024-02-13 05:05:10 +0300 | 
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2024-02-15 00:56:40 +0300 | 
| commit | e3a9ee963ad8ba677ca925149812c5932b49af69 (patch) | |
| tree | 135acef85d1618fde9c263fb295e633637baad58 /scripts/gdb/linux/genpd.py | |
| parent | 6388cfd0e69b56ca640610f1bf29334619d18142 (diff) | |
| download | linux-e3a9ee963ad8ba677ca925149812c5932b49af69.tar.xz | |
kbuild: Fix changing ELF file type for output of gen_btf for big endian
Commit 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF")
changed the ELF type of .btf.vmlinux.bin.o to ET_REL via dd, which works
fine for little endian platforms:
   00000000  7f 45 4c 46 02 01 01 00  00 00 00 00 00 00 00 00  |.ELF............|
  -00000010  03 00 b7 00 01 00 00 00  00 00 00 80 00 80 ff ff  |................|
  +00000010  01 00 b7 00 01 00 00 00  00 00 00 80 00 80 ff ff  |................|
However, for big endian platforms, it changes the wrong byte, resulting
in an invalid ELF file type, which ld.lld rejects:
   00000000  7f 45 4c 46 02 02 01 00  00 00 00 00 00 00 00 00  |.ELF............|
  -00000010  00 03 00 16 00 00 00 01  00 00 00 00 00 10 00 00  |................|
  +00000010  01 03 00 16 00 00 00 01  00 00 00 00 00 10 00 00  |................|
  Type:                              <unknown>: 103
  ld.lld: error: .btf.vmlinux.bin.o: unknown file type
Fix this by updating the entire 16-bit e_type field rather than just a
single byte, so that everything works correctly for all platforms and
linkers.
   00000000  7f 45 4c 46 02 02 01 00  00 00 00 00 00 00 00 00  |.ELF............|
  -00000010  00 03 00 16 00 00 00 01  00 00 00 00 00 10 00 00  |................|
  +00000010  00 01 00 16 00 00 00 01  00 00 00 00 00 10 00 00  |................|
  Type:                              REL (Relocatable file)
While in the area, update the comment to mention that binutils 2.35+
matches LLD's behavior of rejecting an ET_EXEC input, which occurred
after the comment was added.
Cc: stable@vger.kernel.org
Fixes: 90ceddcb4950 ("bpf: Support llvm-objcopy for vmlinux BTF")
Link: https://github.com/llvm/llvm-project/pull/75643
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Justin Stitt <justinstitt@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/gdb/linux/genpd.py')
0 files changed, 0 insertions, 0 deletions
